More than 1,600 patients from families with hereditary retinitis pigmentosa and allied diseases are on file; research is in progress to try to understand the pathogenetic mechanisms in these retinal diseases. A specialized research center has been established with a multidisciplined approach. Diseases under investigation include different forms of retinitis pigmentosa, hereditary macular degenerations, and gyrate atrophy of the choroid and retina. Focal cone electroretinograms are being recorded to obtain more information about retinal malfunction in small retinal areas. Post-mortem donor eyes from patients with hereditary retinal disease are being studied with electronmicroscopy to define ultrastructural abnormalities and to do clinical-pathological correlations. Findings in these donors are being compared with findings in living, affected relatives of donors and in patients on file with the same types of retinitis pigmentosa and allied diseases. Post-mortem donor eyes are also being used to culture the pigment epithelium to see if processes of phagocytosis are abnormal. Research is also being conducted on normal post-mortem human donor eyes to study the capacity of photoreceptors to synthesize phospholipids or proteins and to study synthesis of glycosaminoglycans by the human pigment epithelium in culture; this work is providing a basis for biochemical studies of post-mortem donor eyes from patients with hereditary retinal diseases. Storage of all patient data on file in a computer is being done to allow for efficient retrieval of information for cross correlations, to improve classification of both typical and atypical forms of these diseases, and to develop a profile on the natural history of these diseases.